A Comparative Study of the Navigated and Radiographic Measurements in Open and Closed Wedge High Tibial Osteotomy with Computer Assisted Surgery / 대한정형외과학회잡지

ABSTRACT

PURPOSE: We wanted to identify the difference of the measured values between a navigation system and radiographs when performing open and closed wedge high tibial osteotomy (HTO) under the control of a navigation system. MATERIALS AND METHODS: Thirty-two open wedge HTOs and 51 closed wedge HTOs were performed using a navigation system. The postoperative mechanical axis percent, which was planned on the navigation system, was 62%. The mechanical axis (MA) was measured before osteotomy and after fixation on the navigation system, and these were compared with the measured values from the radiographs. The difference of the postoperative MA between the navigation system and the radiographs was compared according to the type of HTO. The alteration of the tibial posterior slope angle was also compared. RESULTS: For the open wedge HTO, the mean MA after fixation was valgus 2.7degrees on the navigation system and the postoperative MA was valgus 4.0degrees on the radiograph. For the closed wedge HTO, the mean MA after fixation was valgus 3.5degrees on the navigation system and the postoperative MA was valgus 1.6degrees on the radiograph (p=0.000). The mean tibial posterior slope angle was increased by 5.3degrees after the open wedge HTO and it was decreased by 1.8degrees after closed wedge HTO (p=0.000). CONCLUSION: Performing HTO with a navigation system could increase the surgical accuracy because the navigation system checked the intraoperative correction angle in real time. Weight bearing makes a difference for the postoperative MA between the navigation system and radiographs. This should be taken into account, according to the type of HTO.